1. Field of the Invention
This invention pertains to a method and apparatus for down-regulating nutrient absorption in a small intestine of a patient. More particularly, this invention pertains to an apparatus and method for promoting a down-regulation of nutrient absorption by diverting at least a portion of flow of pancreatic exocrine secretion to a distal location within the small intestine.
2. Description of Prior Art
Morbid obesity and its concurrent health risks (including diabetes, heart disease and other ailments) are of near-epidemic proportions in industrialized societies. A wide variety of treatments have been proposed and attempted to treat morbid obesity with a wide variety of efficacy and associated morbidity. These treatments include techniques to reduce stomach volume, alter gastric and intestinal motility, and alter the absorption of nutrients in the small intestine.
Gastric Volume Reduction
Surgical approaches to gastric volume reduction include minimally invasive surgery, open surgery and endoscopic approaches to gastric volume reduction. Many such procedures have been tried and some have been abandoned due to lack of efficacy or unacceptable morbidity and mortality.
The gastric volume reduction procedures include vertical and horizontal gastroplasty in which sutures, staples or other fixation devices are used to join opposing surfaces of the stomach to create a reduced volume pouch and thereby reduce caloric intake. Less invasive techniques are suggested for placing a band around an upper portion of the stomach to act as a belt to reduce the size of the stomach and create a small passageway (a stoma) from a small upper pouch to the remainder of the stomach. Other techniques for reducing gastric volume size include placement of obstructions within the stomach. These include intra-gastric balloons which are filled with saline to reduce the effective volume of the stomach.
Less invasive techniques for restricting the volume of the stomach also include a gastric partition in which the stomach wall is endoscopically cinched together to form a reduced size pouch. The cinching is performed using commercially available products such as the Bard EndoCinch™ and the Wilson-Cook Sew-Right™ cinching equipment. Such surgical equipment is generally described in U.S. Pat. No. 5,088,979 to Filipi et al. issued Feb. 18, 1992; U.S. Pat. No. 6,302,917 to Dua et al. issued Oct. 16, 2001 or PCT International Publication No. WO 01/89393 published Nov. 29, 2001.
It has been recognized that gastric volume reduction does not address all mechanisms associated with obesity. For example, patients with gastric volume reduction can defeat the effectiveness of the gastric volume reduction by modifying eating habits. For instance, a patient may graze continuously on small volume, high caloric food or may replace solid foods with high caloric liquid foods.
Malabsorption Treatments
To address deficiencies associated with gastric volume reduction, treatments have been suggested and developed for reducing the amount of nutrient absorption in the small intestine (particularly in the upper and middle portions of the small intestine—the duodenum and jejunum, respectively).
In the duodenum, ducts from the pancreas and gall bladder discharge into the small intestine through small protrusions referred to as papilla. Commonly, pancreatic exocrine secretions (“PES”) flow from the pancreas in a pancreatic duct. Similarly, bile from the gall bladder flows through a bile duct. These ducts merge to form a common duct with discharges through a papilla into the duodenum. In some patients, the bile duct and pancreatic duct do not merge and separately discharge into the duodenum at separate papilla which, usually, are in close proximity to one another.
Techniques to reduce nutrient absorption (commonly referred to as malabsorption treatments) include drug therapies for reducing lipids absorption. Such drug therapies have uncomfortable side effects, which can discourage a patient from complying with the drug therapy. Other techniques include surgical techniques for rerouting the intestinal system to bypass an extended portion of the small intestine. These include a so-called jejunoileal bypass. Not commonly used due to unacceptable mortality rates, a jejunoileal bypass would result in effective weight loss. Other techniques include the gastric bypass (or Roux-en Y) and duodenal switch. In both of these procedures, a large segment of the small intestine (including the duodenum) are bypassed so that food content is rerouted from a small pouch formed in the upper portion of the stomach to the jejunum. As a result, the absorptive length of the small intestine is significantly shortened thereby reducing the amount of nutrients which are absorbed into the body and which support or lead to weight gain. These procedures combine the benefits of gastric volume reduction with malabsorption. Unfortunately, such surgical procedures are extremely invasive.
Less invasive techniques for restricting absorption have been suggested. They include bariatric sleeve devices such as those disclosed in US Patent Application Publication Nos. 2004/0092892 and 2004/0107004. In these techniques, sleeves are passed through the duodenum so that chyme (the contents of the intestines) are passed through the sleeve and do not interact with the absorptive walls of the intestine. The sleeves may be perforated to permit some of the chyme material to pass through the walls of the small intestine and be absorbed as nutrients.
The bypass of the duodenum results in reduced absorption of desired nutrients (e.g., calcium) as well as undesirable nutrients (such as fat). Particularly, the loss of calcium absorption is significant since such loss can lead to osteoporosis.
Novel treatments include vagal modulation to block neural impulses on the vagus nerve to down-regulate pancreatic exocrine secretion production as well as alter gastric accommodation. Such treatments are shown in U.S. Patent Application Publication No. 2004/0172086 A1.
A suggestion has been made to divert the digestive enzymes from the pancreas past the duodenum. Such a suggestion is shown in US Patent Application Publication No. 2004/0092892 in which a tube is placed through the papilla and into the ducts of the gall bladder and the pancreas. A distal end of the tube is positioned significantly distal to the papilla such that pancreatic exocrine secretion and bile are diverted significantly distally to the papilla resulting in a reduction of absorption.
While pancreatic diversion is clinically interesting, cannulation of the pancreatic duct carries significant risks. Such cannulation of the pancreatic duct has been performed in endoscopic retrograde cholangiopancreatography (ERCP). Patients under-going ERCP and/or related procedures are known to having a higher likelihood of developing pancreatitis. It has been reported that the incidence of post-ERCP pancreatitis can be as high as 28%. Fazel et al., “Prophylactic Pancreatic Duct Stenting: A Panacea”, Gastroenterology, Vol. 124, No. 4, pp. 1274-1275 (2003).
Pancreatitis is a serious disease with no effective treatment. While most patients suffering from acute pancreatitis or ERCP-induced pancreatitis recover after a short period of hospital stay with supportive care, a significant percent proceed to a severe stage of the disease in which necrosis of pancreatic tissue occurs. This extremely serious disease is characterized by an over-active pancreas which excretes digestive enzymes to such an extent that the pancreas itself is digested. The disease can be extremely painful. In many cases, the disease is fatal. The number of US patients who suffer an episode of acute pancreatitis is approximately 185,000 annually. Baron, et al., “Acute Necrotizing Pancreatitis”, New England J. of Medicine, Vol. 340, No. 18, pp. 1412-1417 (1999). No definitive therapy is currently available to treat these patients except supportive care. Furthermore, the overall mortality rate for severe pancreatitis is about 20 to 30%. Id.
In addition to the serious health consequences, pancreatitis is costly. A recent study reported that the average total hospital cost to obtain a survivor of severe, acute pancreatitis is nearly $130,000 with an average length of hospital stay of 40 days. Soran, et al., “Outcome and quality of life of patients with acute pancreatitis requiring intensive care”, J. Surg. Res., 91(1), pp. 89-94 (2000). Further complicating the management of these patients is the uncertainty surrounding the prognosis because the course of the disease is unpredictable at initial presentation. Chatzicostas, et al., “Balthazar computed tomography severity index is superior to Ranson criteria and APACHE II and II scoring systems in predicting acute pancreatitis outcome”, J. Clinical Gastroenterology, 36(3), pp. 253-260 (2003). Pancreatitis may be associated with a number of etiologies including chronic alcoholism or gallstones (e.g., gallstones lodged in the pancreatic or common duct). When acute pancreatitis becomes severe, treatment options are severely limited. Morbidity and mortality rates for pancreatitis are sobering. Baron, et al., “Acute Necrotizing Pancreatitis”, New England J. of Medicine, Vol. 340, No. 18, pp. 1412-1417 (1999) and Steer et al., “Chronic Pancreatitis”, New England J. of Medicine, pp. 1482-1490 (1995).
Accordingly, malabsorption bariatric treatments which contemplate cannulation of the pancreatic duct present unacceptable risks to patients and unacceptable societal costs.
It is an object of the present invention to provide a technique for pancreatic diversion in a manner, which minimizes risks of pancreatic duct obstruction and other associated morbidity.